Articles have been constructed in the past having a plurality of discrete tubes bonded to each other, or to a common support structure, forming channels for the circulation of fluids. Additionally, holes may be machined into a solid body to form channels. U.S. Pat. No. 4,712,158 discloses a cooling plate for electronic circuit components. An undulating cooling passage is formed in the cooling plate, such as by abutting two complementary plates having aligned grooves. U.S. Pat. No. 4,516,632 discloses a fluid heat exchanger formed from a stack of thin metal sheets bonded together. Alternating slotted and unslotted sheets form fluid flow channels within the stack.
However, such articles have been difficult and expensive to manufacture, particularly with extremely small, long or closely spaced passageways, or for thin articles.